DETROIT BEACH, Mich. – A magnitude 3.2 earthquake occurred just offshore from Monroe at 6:55 p.m. Friday evening. USGS officials initially reported the quake as a 3.4 magnitude earthquake.
Here is how the quake looked like on a seismograph:
The “Did you feel it?” map on the U.S. Geological Survey website shows that the quake was felt strongest, as you would expect, Downriver closest to the epicenter, and was felt as far west as US-23 and as far north Waterford.
Although earthquakes are not common in Michigan due to the fact that we are not located near any of our nation’s major fault lines, they do sometimes occur, and are called “within-plate” earthquakes.
You may recall the 2015 quake near Kalamazoo, that was a 4.2 magnitude quake. The largest quake to occur with its point of origin in Michigan was a 4.6 quake in 1947 near Coldwater. If you were in the Lansing area in 1994, you may have felt a 3.5 magnitude quake there. Those biggies that we hear about generally occur along faults, the boundaries between massive slabs (“plates”) of rock way beneath the earth’s surface.
Those plates move a bit, and where the edges of two plates come in contact, pressure builds up until one plate suddenly “slips” and slides along the other plate, or one suddenly slides above or below another. By the way, there is a science called “plate tectonics” which studies these plates and their movement.
Remember that the magnitude scale we always talk about is logarithmic scale? Each increase of 1.0 on the scale is ten times more force. So, when you hear about a magnitude 7.4 quake, that’s 10,000 times more forceful than the quake that occurred here this evening.
View Tweets below of what some residents say they felt:
On Grosse Ile, it was a loud noise/rumble. Freaked out my cat.— Deborah Fogt (@DeborahFogt) August 21, 2020
My name is Robert Higgins, it was quite tensest, we were slouching down and we were very upset. We were just hearing a bunch of commotion. We were very nervous. It felt like a 6.8 earthquake.— Bart (@BartShow) August 21, 2020
Felt in toledo! Our apartment building swayed back and forth twice, but not strong enough to knock anything over— casey 🐸🏳️🌈 (@sonosels) August 21, 2020
In flat rock, our deck started shaking and it made waves in our pool!— Madison Heyer (@MadisonHeyer) August 21, 2020
By Metro Airport here. Felt like a herd of elephants running through the house for a few seconds.— Jon Edney (@TheJonEdney) August 21, 2020
Yes felt it so hard, thought someone hit the corner of our condo in Trenton! Windows and doors rattled....— DawnG (@dawncullengould) August 21, 2020
Shook my property significantly for about 3-4 seconds here in Monroe Twp— 🇺🇲Ofc. B. Mozingo🌷 (@VINEYARDHTSNWA) August 21, 2020
In Taylor, Telegraph & 94. We heard a boom and the house swayed. We went outside and the neighbors were outside wondering what happened also.— Tell JJ about It (@TellJJaboutIt1) August 21, 2020